Processing of data via optical means is well known in the art, the primary advantage being that optical processing of large amounts of data is achieved in a highly parallel, substantially instantaneous manner. Coherent optical processors have been proposed to perform many and varied functions including Fourier-transformation analysis of analog signals and the correlation therebetween. In the text "Coherent Optical Computers," K. Preston, Jr., McGraw-Hill Book Company, 1972, particularly Section 1.70, Other Computational Modes, there is discussed the use of a coherent optical processor to determine the ambiguity plane of a function, EQU .PSI.(.DELTA..omega., .DELTA.t)=.intg.f(t)f(t+.DELTA.t)e.sup.-j.DELTA..omega.t dt
The present invention is directed toward a coherent optical processor that is utilized to determine the ambiguity plane of or the correlation between, two real-time analog signals with time shifts, .DELTA.t and frequency shifts (doppler shifts), .DELTA..omega., as the variables. Attention is also directed toward the publication "Several Optical Correlation Methods," A. Lohmann, International Optical Computing Conference, 1975, IEEE Catalog No. 75CH0941-5c, pages 142 - 144, Method 2, for an illustration of some typical optical processing concepts.